The present invention relates generally to the operation of fluid piping systems. More particularly, the present invention relates to keeping fluid piping systems free of air and other gases.
Since the advent of commercial nuclear power in the late 1960's, the industry has been aware of issues regarding the accumulation of air and other gases in the high points in various safety-related fluid systems. These systems are designed to prevent nuclear fuel damage given various postulated accident scenarios. Air and gas accumulation in these fluid systems could result in failure of those systems and in their failure in turn to prevent fuel damage.
The operators of nuclear power plants are required to demonstrate that they have suitable design, operational, and testing control measures in place for complying with regulations that require, by federal law, these fluid systems to be “full”, i.e. devoid of air and/or gases.
Currently in the nuclear industry, the common ways to detect unwanted air in piping systems is to perform ultrasonic test (UT) examinations at locations where no current vent exists or use existing vents to periodically vent suspect locations without knowing whether air has accumulated in those locations of the system. These solutions are unsatisfactory because they require radiation exposure of workers when there may be no need for testing or venting. Also, UT probes, in general, cannot remain connected to the piping system in question due the temperature limitations of the UT equipment and associated coupling material. As a consequence, they must be reconnected each time a UT examination is to be performed, thus taking additional time and resulting in additional exposure to radiation.
Currently, outside of the nuclear industry, there are a number of solutions for measuring gas accumulation in piping, for indicating the extent of the gas accumulation, and for venting the accumulated gas. However, these solutions use materials and construction practices that fail to meet the needs of the highly specialized requirements of the commercial nuclear industry, particularly if a device is to penetrate the pressure boundary of fluid piping systems.